Study of Zinc Dialkydithiophosphate Antiwear Film Formation and Removal Processes, Part I: Experimental

• Published in: Tribology transactions Vol. 48; no. 4; pp. 558 - 566
• Main Authors: FUJITA, H., GLOVNEA, R. P., SPIKES, H. A.
• Format: Journal Article
• Language: English
• Published: Colchester Taylor & Francis Group 01.10.2005; Taylor & Francis; Taylor & Francis Inc
• Subjects: Antiwear; Antiwear additives; Applied sciences; Boundary Lubrication; Dispersant; Exact sciences and technology; Friction, wear, lubrication; Interferometry; Lubricants & lubrication; Machine components; Mechanical engineering. Machine design; Tribofilm; Tribology; Wear; ZDDP; Zinc; Zinc Dithiophosphate; ZnDTP; Lubricating oil; Viscosity; Dispersant; Antiwear; ZnDTP; Motor oil; Deposition process; Tribological coatings; Lubricant additive; Monitoring; Interferometry; ZDDP; Tribochemical reaction; Film formation; Phosphorus; Zinc compound; Zinc Dithiophosphate; Experimental study; Layer thickness; Lubricant; Kinetic model; Tribofilm; Surveillance; Antiwear additive; Wear; Concentration effect; Boundary lubrication; Tribology
• ISSN: 1040-2004; 1547-397X
• DOI: 10.1080/05698190500385211

Two recent trends in engine oil formulation are a progressive reduction in phosphorus concentration so as to reduce its impact on the de-NO x catalyst, and an increase in dispersant concentration to control the level of lubricant viscosity increase over extended drain intervals. Unfortunately, both of these trends make it more difficult to generate and retain effective antiwear films on lubricated surfaces and both thus strengthen the need to understand the processes by which antiwear films are formed, and removed, during rubbing. This article and its companion outline a study of the kinetics of antiwear film growth and removal. In Part I, a test method for monitoring antiwear film thickness during rolling/sliding is described and employed to explore how various factors, including operating temperature, antiwear additive type and concentration, and the presence of dispersant, influence both the formation and removal of the tribofilms formed by the antiwear additive zinc dialkyldithiophosphate (ZDDP). Part II then analyzes the obtained results to derive a kinetic model of ZDDP film formation and removal (Fujita, et al. [ 1 ]. Presented at the STLE Annual Meeting in Toronto, Ontario, Canada May 17-20, 2005 Review led by Elaine Yamaguchi